Undercutting and conveying element



April 23, 1946. c. E. nBBALs UNDERCUTTING AND CONVEYING ELEMENT Filed June 14, 1945 2 Sheets-Sheet l Inventor April 23,y 1946. c. E. TIBBALS UNDERCUTTING AND CONVEYING ELEMENT #Filed June14y1945 2 sheets-sheet 2 nm/Hwmwmwinllf Vwfrnw (Zar/s E 755550./3.

L l Y W Patented Apr. 23; 1946 OFFICE UNDERCUTTING AND ELEMENT Charles: E. Tibbals, Bluelel'd; V'a. Applicatimnme 14, 1945, serial No. 599,471.

s claims. 01; 26a-si This invention relates to an improved' undercutti'ng. and! conveying element, for coalv mining machines, of' that type embodying a substantially horizontalv plate which is reciprocated so as to have a quick movement in one direction and a slow movement inv the other direction, and which has cutting. bits along one edge arranged to undercut theV coal during the slow movement of the element, the coa-l being delivered by the element to a receiving conveyor during the slow movement thereof.

Coal' veins are often irregular, so that the floor of the minel is found to slope upwardly and then downwardly as the mining proceeds. So far` as I am aware, these undercutting and conveying elements have been more or less rigid substantiallyT throughout, and' it has been diicult, if not impossible, to cause the bits thereof to follow the irregularities of the mine floor.

. The primary object of the present invention, therefore, is tol provide an undercutting and conveying elementy including a plate having an edge portion to which the bits are attached, which edge portion is freely iiexible vertically, and wherein means is provided to iieX such edge portion at will andl tothe desired. degreek so as to cause the bits to properly follow the irregularities of. the mine iloor.

A further' object of the invention is to provide an element of the above kind in which :fluid pressure is utilized to flex the edge of the element.

Another object. of the invention is to provide. an elementY of the above kind which is simple-and durable in construction, easy and economical to construct and use, eflicient in useand otherwise. adapted to meet the requirements for successful. commercial. use.

A still further object is to provide simple and eiicient means for directing the cuttings and. broken down coal away from the coal faceontO the plate for delivery by the latter to the receiving conveyor.

The exact naturev of the present invention, as well as other objects andv features thereof, will. become apparent from the following. description when considered in connection with the accompanying drawings, in which: Y

Figure 1 is a fragmentary topv plan View of an. undercutting and conveying elementv constructed. in accordance with, the present4 invention.

Figure 2 is an. enlarged fragmentary longitudinall section taken n line 2-2of Figurel..

Figure; 3 isa view somewhat similar. toFigurga taken on line 3,-34 ofzFigurel.

- Figure 4:is an enlarged transverse section taken on line 4 4 of Figure 1.

FigureV4 5 isan-i enlarged section taken on line 5-.-5of Figure 1, and:

Figure' 6 isy an. enlarged section taken on line t-Bfof Figure 1.

Referring in detail to the drawings, the present invention has been illustrated, by way of example, as appliedv to onev section of a combined shaking conveyorandf'und'ercutter of the type disclosed in my copending application for U. S. Letters Patent upon Longwall mining machine, Serial No. 548,0-141led August 4, 1944. As disclosed in said copending application, the shaking conveyor .and undercutter includesy a series of overlapping` inetallic plates extending along. theA face ofthe coal pillar and resting on the mine floor to form the conveyor, the edges of the plates next to the coal being. fitted withv replaceable steel bits to form a cutting edge. Also, the conveyor and undercutter is reciprocated by a suitable driving unit in a mannersimi-lar toa common shaking conveyor, and is suitably fed toward the pillar to form an undercut therein along the'oor line. The cone veyor and undercutter isfreciprocated with a rapid movementin one direction and with a slow movementin the opposite direction to undercut and elect delivery of the coal to a receiving conveyor.

Referring to the drawings by reference characters; I indicates a horizontal plate formingpart of a section of the. conveyor and undercutter,and 2 indicates thecoal pillar; along the face of whichY the conveyor and. undercutter extends; The edge. ofthe-plate l neX-t to the coal is fitted with` replaceable cutting bits 3 to form a cutting edge,v said cuttingA bits being secured in socket members 3a. which are tted and secured'on the edge of the plate I neXt to the coal. The back edges3bV arefdisposed. obliquely of the plate i so that the socket members-'cause movement of cuttings.. andbrokendown' coal away from the coal faceonto. the plate l. during the rapid movement totheleftofligure 1..

In. accordance with :the present invention,.the major. portion. ofv thefplate I is relatively thick and. riglid butlthe edgeportion thereof which carries.` the bits. 3 and which is indicated atll is relatively thin. and free flexible vertically. See curedy on the upper and lower faces of the yplate f l alongthe-fexible edge portion l andthe adjacent-part of the. thicker' or rigidv portion of said platet are vmetallic strips Sand 5a that are thin and freely exible. These strips are'preferably secured tothe platelbywelding-,and atall points except withlnfthef areas bounded by .the dotted'y lines indicated at 6 in Figure 1. It will be noted that these areas are elongated longitudinally of the plate I or parallel with thecutting edge of the element. Thus, similar portions of the strips 5 and 5a are left unattached to the plate I to provide uidtight spaces or chambers between the strips 5 and 5a and the plate I into which may be introduced fluid under pressure for bulging either strip at its unattached portions away from the plate I and thereby causing flexing o the edge portion 4 of the latter. As shown in Figure 5, when the fluid pressure is introduced into the chambers or spaces between the upper strip 5 and the plate I, said upper strip is bulged upwardly so as to ex the edge portion 4 of the plate I upwardly and thereby properly direct the cutting lbits 3 to follow the oor of the mine when it slopes upwardly as at 'l'. On the other hand, when the fluid under pressure is introduced between the lower strip 5a and the plate I as shown in Figure 6, said strip 5a is bulged downwardly away from the plate I and causes the edge portion 4 of said plate I to be exed downwardly so that the bits 3 will be caused to follow thefloor of the mine when the latter slopes Vdownwardly as indicated at la. When the fluid under pressure is exhausted from between both strips and the plate I as shown in Figure 4, the parts are normally positioned so that the bits will be disposed to enter the coal at the floor line when the floor is level.

To facilitate supply of iluid under pressure to or exhaust of the same from the chambers or points where the strips are unattached to the plate I, the latter is provided with a transverse groove 8 in its upper face communicating with each upper chamber and a transverse groove 8a in its lower face communicating with each lower chamber, said grooves being covered by narrow extensions 9 and 9a provided on the outer edges of the strips 5 and 5a and welded to the plate I. A relatively small bulging of the strips 5 and 5a causes considerable flexing of the portion 4 of plate I, so that the strips 5 and 5a have ample flexibility to permit sufficient inflation and sufcient upward or downward movement of the cutting bits for all practical purposes. Obviously, a suitable supply and exhaust conduit may Ibe suitably connected with the passages formed by the covered grooves 8 and 8a, which conduit may have a suitable control valve therein whereby to selectively cause deflation of both the upper and lower chambers, inatflon of only the upper chambers, or inflation of only the lower chambers, as required. As this is elementary and forms no specific part of the present invention, it is deemed unnecessary to illustrate or detail the same herein.

As shown more clearly in Figure 1, a notch I is provided in the edges of plate I and strips and 5a at the front of each bit socket 3a, and the edges of the plate and the strips are beveled rearwardly and downwardly as at Il at the forward sides of these notches. This aids in directing the coal dust upwardly onto the plate I during the rapid movement of the latter rearwardly or to the left of Figure 1, the beveled edges at I I being directly behind the oblique back edges 3b of the sockets 3a, so that the elevated dust is directed inwardly onto the plate I and away from the coal face as before mentioned. Flexible ribs I2, preferably constructed of rubber and vulcanized or otherwise suitably attached to the upper strip 5a, extend obliquely of the element so as to provide continuations of the back edges 3b ofthe sockets 3a for causing still further travel of the coal and coal dust away from the coal face on the plate I. These ribs I2 are made of flexible material in order to provide the latter of suiiicient thickness and because they are applied to those portions of the strip 5 which are free of the plate I and are therefore bulged upwardly in the use of the invention as illustrated in Figure 5.

In use, the pressure fluid is exhausted from between the strips 5 and 5a. and the plate I when the floor is level as shown in Figure 4. Should the floor of the mine suddenly slope upwardly as at `I in Figure 5, the bits 3 are properly elevated by introducing fluid under pressure between the strip 5 and plate l where the said strip is unattached to the latter as shown in Figure 5. This is done by simply introducing the pressure iiuid through the passages formed by the covered grooves 8. However, when the floor of the mine is found to slope downwardly as at 'Ia in Figure 6, the pressure fluid is exhausted from between the upper strip 5 and plate I through the covered grooves 8, and the pressure uid is introduced between the lower strip 5a and plate I through the covered grooves 8a.

From the foregoing description, it is believed that the construction and operation, as well as the advantages, of the present invention will be readily understood and appreciated by those skilled in the art. While the invention has been illustrated and described as finding embodiment in one of the plates or sections of a shaking conveyor and undercutter having rectilinear reciprocating movement, it will be apparent that the invention is capable of other applications. For instance, it may be adapted to the curved edge portion of each of the oscillating undercutting and conveying element embodying the plates indicated at 3 and 4 in my copending application for patent upon Entry driving machine, Serial No. 548,768 filed August 9, 1944, wherein the cutter bits are reciprocated in a curvilinear path. In a like manner, the invention may be adapted to the curved edge portion of the segmental element or section indicated at I a in my copending application for patent upon Longwall mining machine, Serial No. 589,483 filed April 21, 1945.

Minor changes may be made in details of construction illustrated and described, such as fall within the scope of the invention as claimed.

What I claim is:

1. An undercutting and conveying element, for coal mining machines, adapted to be reciprocated on the mine floor with a rapid rearward stroke and a slow cutting and conveying stroke, comprising a substantially horizontal plate having an edge portion which is freely exible vertically, cutting bits mounted on the free edge of said ilexible edge portion, and means to selectively ilex said nexible portion downwardly or upwardly, at will.

2. An undercutting and conveying element, for coal mining machines, adapted to be reciprocated on the mine floor with a rapid rearward stroke and a slow cutting and conveying stroke, comprising a substantially horizontal plate having an edge portion which is freely flexible vertically, cutting bits mounted on the free edge of said flexible edge portion, and fluid pressure operated means to selectively flex said flexible edge'portion downwardly or upwardly, at will.

3. AAn undecutting and conveying element, for coal mining machines, adapted to be reciprocated on the mine oor with a rapid rearward stroke und a slow cutting and conveying stroke, 'comprislng a substantially horizontal plate having an edge portion which is freely flexible vertically, cutting bits mounted on the free edge of said flexible edge portion, freely flexible strips secured on the upper and lower surfaces of said flexible edge portion and an adjacent portion of said plate so as to leave confined areas of the strips unattached to the plate inwardly of said exible edge portion, and means to facilitate supply of pressure fluid to or exhaust of the same from between the unattached portions of the strips and the plate, whereby to selectively bulge the strips and cause upward or downward flexing of the flexible edge portion of the plate, at will.

4. An undercutting and conveying element, for coal miningV machines, adapted to be reciprocated on the mine floor with a rapid rearward stroke and a slow cutting and conveying stroke, comprising a substantially horizontal plate having an edge portion which is freely flexible vertically, cutting bits mounted on the free edge of said flexible edge portion, freely flexible strips secured on the upper and lower surfaces of said flexible edge portion and an adjacent portion of said plate so as to leave confined areas of the strips unattached to the plate inwardly of said flexible edge portion, and means to facilitate supply of pressure fluid to or exhaust of the same from between the unattached portions of the strips and the plate, whereby to selectively bulge the strips and cause upward or downward flexing of the flexible edge portion of the plate, at will, said last named means comprising grooves in the surfaces of the plate and extensions on the strips covering said grooves to form supply and exhaust passages for the pressure fluid.

5. An undercutting and conveying element, for coal mining machines, adapted to be reciprocated on the mine floor with a rapid rearward stroke and a slow cutting and conveying stroke, comprising a substantially horizontal plate having an edge portion which is freely flexible vertically, cutting bits mounted on the free edge of said flexible edge portion, freely flexible strips secured on the flexible edge portion and an adjacent portion of the plate to the upper and lower surfaces thereof, said strips having lareas unattached to the plate at enclosed points so that the unattached portions of the plates form diaphragms adapted to be flexed away from the plate to selectively flex the flexible edge portion of the plate upwardly or downwardly at will, and means to facilitate selective supply of pressure fluid to or from between the unattached portions of the strips and the plate.

6. An undercutting and conveying element, for coal mining machines, adapted to be reciprocated on the mine floor with a rapid rearward stroke and a slow cutting and conveying stroke, comprising a substantially horizontal plate having an edge portion which is freely flexible vertically, cutting bits mounted on the free edge of said flexible edge portion, freely exible strips secured on the flexible edge portion and an adjacent portion of the plate to the upper and lower surfaces thereof, said strips having areas unattached to the plate at enclosed points so that the unattached portions of the plates form diaphragms adapted to be exed away from the plate to selectively flex the flexible edge portion of the plate upwardly or downwardly at will, and

` means to facilitate selective supply of pressure fluid to or from between the unattached portions of the strips'and the plate, and flexible ribs secured on the upper strip obliquely of the plate to cause movement of coal away from the working face from the bits on the rapid rearward stroke of the element, said ribs being attached to the areas of the upper strip which vare unattached to the plate.

7. An undercutting and conveying element, for coal mining machines, adapted to be reciprocated on the mine floor with a rapid rearward stroke and a slow cutting and conveying stroke, comprising a substantially horizontal plate, cutting bits mounted on a free edge of said plate, said plate having notches in said free edge thereof, one in front of each cutting bit, the edge of the plate at the forward side of each notch being beveled rearwardly and downwardly whereby to cause coal dust to be delivered upwardly onto the plate upon its rapid rearward stroke.

8. An undercutting and conveying element, for coal mining machines, adapted to be reciprocated on the mine floor with a rapid rearward stroke and a. slow cutting and conveying stroke, comprising a substantially horizontal plate, cutting bits mounted on a free edge of said plate, said plate having notches in said free edge thereof,one in front of each cutting bit, the edge of the plate at the forward side of each notch being beveled rearwardly and downwardly whereby to cause coal dust to be delivered upwardly onto the plate upon its rapid rearward stroke, and sockets for said bits secured on the plate in front of each notch, said sockets having oblique rear edges to cause travel of the coal dust away from the working face as it is delivered onto the plate by traveling up the beveled edges.

CHARLES- E. TIBBALS. 

